45-70 Trapdoor

[Nuclearcricket]

Jim, that grove you see is just part of the manufacturing process, everyone does things a little differently. The 45 cases from the 70 to the 120 all have the same rim diameter and the same case head diameter, just the lengths are different. Your extractor should do about the same with the 90 case as it will do with the 70 case. The aerodynamics might be slightly different due to the different lengths but that's all.
Sam